This application relates to user interfaces such as the fast multi-touch sensors and other methods and techniques disclosed in: U.S. Pat. No. 9,019,224 entitled “Low-Latency Touch Sensitive Device”; U.S. Pat. No. 9,235,307 entitled “Fast Multi-Touch Stylus And Sensor”; U.S. Pat. No. 9,710,113 entitled “Fast Multi-Touch Sensor With User-Identification Techniques”; U.S. Pat. No. 9,811,214 entitled “Fast Multi-Touch Noise Reduction”; U.S. Pat. No. 9,158,411 entitled “Fast Multi-Touch Post Processing”; U.S. patent application Ser. No. 14/603,104, entitled “Dynamic Assignment of Possible Channels in a Touch Sensor”; U.S. Pat. No. 9,710,116 entitled “Frequency Conversion in a Touch Sensor”; U.S. Pat. No. 9,933,880 entitled “Orthogonal Signaling Touch User, Hand and Object Discrimination Systems and Methods”; U.S. patent application Ser. No. 14/812,529 entitled “Differential Transmission for Reduction of Cross-Talk in Projective Capacitive Touch Sensors”; U.S. patent application Ser. No. 15/162,240, entitled “Transmitting and Receiving System and Method for Bidirectional Orthogonal Signaling Sensors”; U.S. Provisional Patent Application No. 62/473,908, entitled “Hand Sensing Controller,” filed Mar. 20, 2017; and U.S. Provisional Patent Application No. 62/488,753, entitled “Heterogenous Sensing Apparatus and Methods” filed on Apr. 22, 2017. The entire disclosures of the aforementioned patents and patent applications are incorporated herein by reference.
In recent years, the capacitive touch sensors for touch screens have gained popularity, in addition to the development of multi-touch technologies. A capacitive touch sensor comprises rows and columns of conductive material in spatially separated layers (sometimes on the front and back of a common substrate). To operate the sensor, a row is stimulated with an excitation signal. The amount of coupling between each row and column can be affected by an object proximate to the junction between the row and column (i.e., taxel). In other words, a change in capacitance between a row and column can indicate that an object, such as a finger, is touching the sensor (e.g., screen) near the region of intersection of the row and column. By sequentially exciting the rows and measuring the coupling of the excitation signal at the columns, a heatmap reflecting capacitance changes, and thus proximity, can be created.
Generally, taxel data is aggregated into heatmaps. These heatmaps are then post-processed to identify touch events, and the touch events are streamed to downstream processes that seek to understand touch interaction, including, without limitation, gestures, and the objects in which those gestures are performed.
In 2013, the application leading to U.S. Pat. No. 9,019,224 was filed (hereinafter the “'224 Patent”). The '224 Patent describes a fast multi-touch sensor and method. Among other things, the '224 Patent describes simultaneous excitation of the rows using unique, frequency orthogonal signals on each row. According to the '224 Patent, the frequency spacing (Δf) between the signals is at least the reciprocal of the measurement period (τ). Thus, as illustrated in the '224 Patent, frequencies spaced by 1 KHz (i.e., having a Δf of 1,000 cycles per second) required at least a once per millisecond measurement period (i.e., having T of 1/1,000th of a second). Numerous patent applications have been filed concerning interaction sensing using a sensor driven by a simultaneous orthogonal signaling scheme, including, without limitation, Applicant's prior U.S. patent application Ser. No. 13/841,436, filed on Mar. 15, 2013 entitled “Low-Latency Touch Sensitive Device” and U.S. patent application Ser. No. 14/069,609 filed on Nov. 1, 2013 entitled “Fast Multi-Touch Post Processing.”
These systems and methods are generally directed to multi-touch sensing on planar sensors. Obtaining information to understand a user's touch, gestures and interactions with an object introduces a myriad of possibilities, but because handheld objects, for example, come in a multitude of shapes, it can be difficult to incorporate capacitive touch sensors into objects such as a controller, ball, stylus, wearable device, and so on, so that the sensors can thereby provide information relative to a user's gestures and other interactions with the handheld objects.
While fast multi-touch sensors enable faster sensing on planar and non-planar surfaces, they lack capabilities to provide detailed detection of non-contact touch events occurring more than a few millimeters from the sensor surface. Fast multi-touch sensors also lack capabilities to provide more detailed information relative to the identification, and/or position and orientation of body parts (for example, the finger(s), hand, arm, shoulder, leg, etc.) while users are performing gestures or other interactions.